The present invention is referred to a programmable gas burner for gas stoves, and more particularly to a burner for gas stoves which is possible to program in accordance with to a pre-established operation time chosen by the user.
The typical system to ignite oven burners of stoves that use gas mainly includes to partially turn on a gas valve to leave gas through a pilot burner and to ignite the pilot burner manually with a lighted match or by means or a manual electric igniter. Once the pilot burner is ignited, the gas valve is completely open in order to ignite the burner of the oven.
However, one of the main problems of the typical system is that, sometimes, the main burner does not ignite, whether the pilot burner is turned off at the moment that the burner is ignited or by air flows, which results in an accumulation of gas in that area, and this could cause the user to immediately close the valve. In this manner, once the user would try again to light the oven, he would have ventilate the area so as to disperse the gas that might have accumulated, thus preventing a possible explosion.
At the present, there are some ignition systems for the ignition of gas burners that use an electronic ignition system. For example, U.S. Pat. No. 3,914,092 assigned to Johnson Service Controls it is referred to a direct spark ignition system for generating ignition sparks for igniting fuel discharged by a fuel outlet.
Another system for controlling a pilot burner and main gas valves of gas furnace is shown in U.S. Pat. No. 3,986,813 assigned to the Cam-Stat Incorporated company, including a pilot spark igniter and a pilot flame sensor. This system includes a relay having a first standby mode providing power to a spark igniting circuit so that, when the thermostat switch is closed, a pilot valve solenoid is energized, and in a second operating mode disconnecting power from the power from the spark ignition circuit and providing power to the main valve solenoid when the flame is sensed at the pilot burner. The system is provided with a fast responding circuit for operating the relay utilizing a 24 volts supply, with a 48 volts supply provided only for the flame sensor.
Other arrangements of gas burners that already use electronic ignition systems to operate are described and claimed in U.S. Pat. Nos. 4,055,164, 4,082,493, 4,111,639 and 4,194,875, all of them related to control systems for the automatic ignition of the burners. However, in all the cases, these are referred for controlling the pilot and the main burner gas valves (U.S. Pat. Nos. 4,082,493 and 4,194,875); for controlling the ignition of an auxiliary fire nozzle and a main fire nozzle in a water heater (U.S. Pat. No. 4,055,164); or to a self-checking fuel ignition system, which effects periodic testing of the operability of the spark-generation circuit.
Taking into account the previous art, the present invention refers to a programmable burner for gas stoves, which can be programmed in keeping with operation times established by the user. Under this scheme, there already are some systems that were developed and are related to systems used to control gas burners, for example, the U.S. Pat. No. 4,318,687 assigned to the Inoue-Japax Research Incorporated company is claiming a burner system of the type in which a thermocouple or like EMF-generating sensor detects the presence of a pilot flame and controls a main fuel valve to hold the latter open as long as the pilot flame remains lit. According to the invention, the main valve is held open by a solenoid and a resistor is provided in circuit between the sensor and the solenoid to reduce the response time of the latter which results from the inductance contributed by the magnetic coil forming the solenoid.
Another development that is related to gas stoves is described in U.S. Pat. No. 4,830,602, assigned to Cramer GmbH, which is related to a gas range with at least one burner covered by a glass ceramic plate, wherein the burner has a gas cock and a timed-ignition and monitoring device, such that the output of the burners is adjustable. A gas cock is used with plugs rotatable between a high and a low position with the aid of a knob and a knob shaft, with a spindle connected to the knob shaft, with a valve plate under the gas inlet opening in the plug housing, with a microswitch for the ignition device and with the use of an electromagnet under the valve plate, in the area of the gas supply connection of the further housing. The knob with the knob handle and the spindle is pressable against the action of a return spring in the high position of the plug. This way, the microswitch for the timed ignition device becomes actuatable and the valve plate becomes pressable on the electromagnet against the action of a return spring, thereby opening the combustion gas inlet opening. The monitoring device has thermoelement reaching deeply into the flame of the burner, which generates a thermal current after maximum 10 sec., feeding the electromagnet and holding the valve plate. The design of the thermoelement and of the electromagnet are such that the electromagnet releases the valve plate and interrupts the gas supply when the flame of the burner is interrupted for up to 60 seconds or for more than 60 seconds.
Finally, U.S. Pat. No. 5,094,259, assigned to Chung-Hsiung Hsu, refers to an automatic shut-off device for a gas stove, and more particularly, a safety valve control device that can be retrofitted between the gas inlet pipe and the catch base of the stove. The device includes a coupling such that operation of the knob of the gas stove at the time operates the circuit of a gas safety valve control device. This operation causes the forward movement of a function shaft of the gas safety valve device and opens the gas intake valve to supply the gas to the stove burner. The function shaft is also subject to the control by an electromagnetic control rod to maintain the open state of the gas intake valve. In case the fire goes out accidently, the circuit device energizes an electromagnetic coil to attract upwardly an electromagnetic control rod, thereby disconnecting the function shaft, which is spring loaded, and which in turn operates the gas intake valve. This action thus disconnects the gas supply to the stove. Also, if the cooking time is too long, and the fire does not go out (e.g., one forgets to turn off the gas) or the gas at the stove burner can not be ignited within the given time, the device will also shut off automatically the gas intake valve.
As can been seen from the above, the previously described devices are related with safety devices that automatically close the valve of a gas stove and maintain the valve open through the use of an electric magnet that maintains the seal of an opening/closure retracted by means of a current that is provided by a the stated electromagnet""s thermocouple.
However, none of the devices is related with a programmable burner wherein the user could establish a predetermined operation time. The programmable burner of the present invention includes an arrangement formed by a safety valve, a thermocouple located in conjunction with the external edge of the burner. Said safety valve is maintained open by the detection of the presence of a flame on the gas burner. An electrode is placed close to and in conjunction with the burner for igniting. A spark generation module is connected to the electrode that generates the sparks that are necessary for igniting the burner. A spark interrupter is connected to the spark generation module, with the spark interrupter placed over the burner knob that is connected to the safety valve, which, at the moment of igniting the stove""s burner, activates the spark generation module, generating the sparks that are necessary for igniting the burner. A clock that includes a time-measuring function in a regressive countdown, is connected to the thermocouple and to the safety valve in order to program the igniting time of the burner with a pre-programmed time; and an interrupter connected to the clock, the safety valve and the thermocouple in order to permit the burner to function for a programmed time or continuously as a normal burner, without having to program an operation time.
Therefore, a first objective of the present invention is to provide a programmable burner for gas stoves through which the user can establish the burner""s operation time under a pre-determined period of time.
An additional objective of the present invention is to provide a programmable burner for gas stoves that uses a clock that includes a time-measuring function in a regressive time countdown (chronometer) and a safety valve that is maintained open through a thermocouple.
An additional objective of the present invention is to provide a programmable burner for gas stoves that permits the function of a burner for a programmed time or continuously as a normal burner, without having to program its operation time.
These and other objectives and additional advantages of the present invention will become evident to those who are experts in the field in the following detailed description of the invention, which will be made with reference to a specific embodiment in an illustrative but not limiting manner for said invention.